I'm doing an intake refresh on my 82 and i'm going through all my vacuum lines checking that they are hooked up right (they are not) and on the #4 there right by the fpr there is a small sensor or something screwed into the head with
2 vacuum lines coming off of it going to the fpr and dampener I have a feeling they are not hooked up right, does any one know what that small round sensor is?

 

It is a heat operated vacuum switch.....was used on some models to open up the valve to the lines to the charcoal can to purge fuel vapors but only after the engine is warm...

 

ok thanks so i guess it would be hooked up to the same port as the vac advance.